Hydrocratic generator

ABSTRACT

A mixing apparatus for mixing first salinity fluid with a second salinity fluid, the mixing apparatus comprises a down tube having a side wall, an open upper end and an open lower end, and a plurality of apertures selectively located in the side wall of the down tube. At least some of the apertures have an arm with an opening therein about the aperture to facilitate inflow of fluid to the down tube through the openings. A fluid inlet and a fluid outlet are provided at the open upper end and open lower end respectively of the down tube so that the first salinity fluid in use enters the down tube through the fluid inlet and the apertures and is discharged therefrom through the fluid outlet. A feed tube is provided and has a first end connectable to a source of second salinity fluid having a salinity different to the first salinity fluid and a second end for introducing the second salinity fluid to the fluid inlet of the down tube to mix the first salinity fluid with the second salinity fluid to form a fluid mixture.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application of U.S. patent applicationSer. No. 11/158,832 filed Jun. 21, 2005, which is a continuation-in-partof U.S. patent application Ser. No. 11/096,981 filed Mar. 31, 2005,which is a continuation-in-part application of U.S. patent applicationSer. No. 10/777,458 filed Feb. 12, 2004, which is a continuation-in-partapplication of U.S. patent application Ser. No. 10/357,007 filed Feb. 3,2003 and also a continuation-in-part of U.S. patent application Ser. No.10/404,488 filed Mar. 31, 2003. U.S. patent application Ser. No.10/357,007 is continuation-in-part of, and U.S. patent application Ser.No. 10/404,488 is a continuation of, U.S. patent application Ser. No.09/952,564 filed Sep. 12, 2001, now U.S. Pat. No. 6,559,554, which is acontinuation-in-part of U.S. patent application Ser. No. 09/415,170filed Oct. 8, 1999, now U.S. Pat. No. 6,313,545. U.S. patent applicationSer. No. 09/415,170 itself claims the benefit of Provisional PatentApplications Nos. 60/123,596 filed Mar. 10, 1999 and 60/141,349 filedJun. 28, 1999. All of the above applications are incorporated herein byreference.

BACKGROUND OF THE INVENTION

The present invention relates to hydraulic power generation systems and,in particular, to an apparatus and method for generating power using anovel pseudo-osmosis process which efficiently exploits the osmoticenergy potential between two bodies of water having different salinityconcentrations.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect to provide an improved apparatus and methodfor generating power using a novel forward osmosis process whichefficiently exploits the osmotic energy potential between two bodies ofwater having different salinity concentrations.

Advantageously, the method and apparatus of the present invention doesnot require the use of a semi-permeable membrane or other speciallyformulated material, nor does it require heating or cooling of the freshwater or salt water solution. Moreover, the present invention mayrecover energy from a wide variety of fresh water sources, includingtreated or untreated river run-off, treated waste-water run-off oreffluent, storm-drain run-off, partly contaminated fresh water run-off,and a wide variety of other fresh water sources. Thus, the presentinvention is well suited to large scale power production in a widevariety of geographic locations and under a wide variety of conditions.The invention has particular advantage for use in remote regions whereelectrical power generation by conventional means may be commerciallyinfeasible or impractical.

According to one aspect of the invention, there is provided a mixingapparatus for mixing first salinity fluid with a second salinity fluid,the mixing apparatus comprising: a down tube having a side wall, an openupper end and an open lower end, and a plurality of aperturesselectively located in the side wall of the down tube, at least some ofthe apertures having an arm member with an opening therein about theaperture to facilitate inflow of fluid to the down tube through theopenings; a fluid inlet and a fluid outlet at the open upper end andopen lower end respectively of the down tube, wherein the first salinityfluid in use enters the down tube through the fluid inlet and theapertures and is discharged therefrom through the fluid outlet; and afeed tube having a first end connectable to a source of second salinityfluid having a salinity different to the first salinity fluid and asecond end for introducing the second salinity fluid to the fluid inletof the down tube to mix the first salinity fluid with the secondsalinity fluid to form a fluid mixture.

According to another aspect of the invention, there os provided ahydrocratic generator system comprising: a container having an upperchamber and a lower chamber sealed from the upper chamber, the upperchamber for accommodating a body of fluid having a first salinity; afirst feed inlet in the upper chamber of the container through which thefluid having a first salinity can be discharged into the container; adown tube having an upper inlet end and a lower outlet end, the downtube being located primarily in the upper chamber of the container withthe outlet end thereof discharging into the lower chamber; a second feedinlet through which fluid having a second salinity can be dischargedinto the upper chamber of the container such that the fluid having thesecond salinity mixes with the fluid having the first salinity in thedown tube; and a discharge means from the lower chamber to facilitatedischarge of the mixed fluids.

According to yet another aspect of the invention, there is provided amixing apparatus for mixing first salinity fluid with a second salinityfluid, the mixing apparatus comprising: a down tube having a side walland an open upper end and an open lower end, the down tube having afunnel shaped portion at the upper end, a cylindrical portion below thefunnel shaped portion, a substantially square portion below thecylindrical portion and a venturi tube portion below square portion.

In yet another aspect of the invention, there is provided a mixingapparatus for mixing first salinity fluid with second salinity fluid,the mixing apparatus comprising: a down tube having a side wall and anopen upper end and an open lower end, the side wall being comprised of ameshed screen portion and solid portion below the meshed screen portion;a fluid inlet and a fluid outlet at the open upper end and open lowerend respectively of the down tube, wherein the first salinity fluid inuse enters the down tube through the fluid inlet and meshed screenportion and is discharged therefrom through the fluid outlet; a feedtube having a first end connectable to a source of second salinity fluidhaving a salinity different to the first salinity fluid and a second endfor introducing second salinity fluid to the fluid inlet of the downtube to mix the first salinity fluid with the second salinity fluid toform a fluid mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram representation of a conventional forwardosmosis process through a semi-permeable membrane;

FIG. 1B is a schematic diagram representation of a conventional reverseosmosis process through a semi-permeable membrane;

FIG. 2 is a schematic representation of an experimental up tubeupwelling apparatus for use in accordance with the present invention;

FIG. 3 is a graph of theoretical power recovery for different sizeddown-tubes and fresh water flow rates using the experimental upwellingdevice of FIG. 2;

FIG. 4 is a schematic representation of one embodiment of a hydrocraticgenerator having features and advantages in accordance with the presentinvention;

FIG. 5 is a schematic representation of an alternative embodiment of ahydrocratic generator having features and advantages in accordance withthe present invention;

FIG. 6 is a schematic representation of a further alternative embodimentof a hydrocratic generator having features and advantages in accordancewith the present invention;

FIG. 7A is a schematic representation of a further alternativeembodiment of a hydrocratic generator having features and advantages inaccordance with the present invention;

FIG. 7B is a side view of the up tube of FIG. 7A, showing the slots inthe side of the up tube;

FIG. 7C is a sectional view from below of the shaft support of FIG. 7A;

FIG. 7D is a sectional view from above of the vane drum of FIG. 7A;

FIG. 8A is a schematic representation of a further alternativeembodiment of a hydro-osmotic generator having features and advantagesin accordance with the present invention;

FIG. 8B is a side view of the up tube of FIG. 8A showing two sets ofslots in the side of the up tube;

FIG. 8C is a sectional view from below of the shaft support of FIG. 8A;

FIG. 8D is a sectional view from above of the vane drum of FIG. 8A;

FIG. 9A is a schematic view of an up tube with an open lower end with analternative embodiment of a down tube having a plurality of holes in thesides and the outlet end, having features and advantages in accordancewith the present invention;

FIG. 9B is a sectional view from below of the up tube and the outlet endof the down tube of FIG. 9A;

FIG. 10A is a schematic view of an up tube with an open lower end withan alternative embodiment of the down tube with a plurality of secondarydown tubes having holes in the sides and the outlet end, having featuresand advantages in accordance with the present invention;

FIG. 10B is a sectional view from below of the up tube and the outletend of the down tube of FIG. 10A showing the plurality of secondary downtubes and the holes on the outlet ends of the secondary down tubes;

FIG. 11 is a schematic view of an up tube with an open lower end with analternative embodiment of the down tube with a plurality of secondarydown tubes, having features and advantages in accordance with thepresent invention.;

FIG. 12 is a schematic view of a down tube with a rotating hub and spokeoutlets with no up tube;

FIG. 13 is a schematic view of a down tube with a rotating hub and spokeoutlets with an up tube, having features and advantages in accordancewith the present invention;

FIG. 14 is a schematic view of a portion of an up tube comprising aplurality of concentric up tubes, having features and advantages inaccordance with the present invention;

FIG. 15 is a schematic representation of a modified up tube havingfeatures and advantages in accordance with the present invention;

FIG. 16 is a schematic illustration of a possible large-scale commercialembodiment of a hydro-osmotic generator having features and advantagesin accordance with the present invention;

FIG. 17 is a cutaway view of the turbine and generator assembly of thehydro-osmotic generator of FIG. 12;

FIG. 18 is a schematic view of an up tube with an open lower end, withan alternative embodiment of the rotating down tube, extendingsubstantially into the up tube, and having holes and turbines mountedthereon, having features and advantages in accordance with the presentinvention;

FIG. 19A is a schematic view of an up tube with a closed lower end, withan alternative embodiment of the rotating down tube, extendingsubstantially into the up tube, and having holes and turbines mountedthereon, having features and advantages in accordance with the presentinvention;

FIG. 19B is a side view of the up tube shown in FIG. 19A;

FIG. 20 is a schematic view of an up tube with an open lower end, withan alternative embodiment of the rotating down tube, extendingsubstantially into the up tube, and having holes and turbines mountedthereon, with rotating up tube and down tube, having features andadvantages in accordance with the present invention;

FIG. 21 is a schematic view of an up tube upwelling apparatus inaccordance with the present invention wherein a rotating helical screwis used to generate the power instead of a plurality of fan blades,having features and advantages in accordance with the present invention;

FIG. 22A is a side view of an alternative embodiment of a fan blade usedin accordance with the present invention;

FIG. 22B is a schematic view showing the under portion of the fan bladeillustrated in FIG. 22A of the drawings;

FIG. 23 is a schematic representation showing a further device of theinvention, including multiple turbines;

FIG. 24 a is a schematic representation of yet a further embodiment ofthe invention, including a wrapped tube;

FIG. 24 b is a cross-section through a part of the apparatus as shown inFIG. 24 a;

FIG. 25 is a schematic representation showing yet a further embodimentof the invention, including a sleeve tube;

FIG. 26 is a schematic representation showing yet a further embodimentof the invention including a plurality of differently located feedtubes;

FIG. 27 a is a schematic representation showing a further embodiment ofthe invention, including feed tubes incorporating rings;

FIG. 27 b is a schematic representation showing a cross-section throughthe device of the invention as shown in FIG. 27 a;

FIG. 28 is a schematic representation of yet a further embodiment of theinvention used in the context of a power generator using sewage orsanitation effluent and may use a brine line from a water desalinizationplant;

FIG. 29 is a schematic view of a further embodiment of the hydrocraticgenerator of the invention;

FIG. 30 is a schematic view of yet a further embodiment of thehydrocratic generator of the invention; and

FIG. 31 is a view from the bottom of the brine line shown in FIG. 30 ofthe drawings;

FIG. 32 is a schematic top view of a further embodiment of a hydrocraticgenerator in accordance with the invention;

FIG. is a side view of the hydrocratic generator shown in FIG. 32 of thedrawings;

FIG. 34 is a top view of a further embodiment of a hydrocratic generatorin accordance with the principles of the invention;

FIG. 35 is a side view of the hydrocratic generator shown in FIG. 34 ofthe drawings;

FIG. 36 is a schematic side view of a hydrocratic generator inaccordance with another embodiment of the invention;

FIG. 37 is a schematic side view of a still further embodiment of ahydrocratic generator in accordance with the present invention;

FIG. 38 is a schematic side view of still a further embodiment of thehydrocratic generator of the invention;

FIG. 39 is a schematic view of a tube with substantially uniformdiameter;

FIG. 40 is a schematic view of a tube having a tapering diameter;

FIG. 41 is another schematic view of a tube having a tapering diameterand a series of successively wider tubes;

FIG. 42 is a schematic representation of yet another embodiment of theinvention;

FIG. 43 is a schematic view of a hydrocratic generator in accordancewith another embodiment of the invention, contained in a reservoir;

FIG. 44 is a schematic view of a hydrocratic generator in accordancewith another embodiment of the invention, when constructed in the ocean;

FIG. 45 is a schematic illustration of a hydrocratic engine withfeatures and structure in accordance with yet a further embodiment ofthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

When solvent fluids having differing osmotic potentials are contactedand mixed with each other energy is released. This released energyresults from an increase in entropy of water (or other solvent) when itis transformed from its pure (fresh-water) state to its diluted(salt-water) state. Thus, an entropy gradient is created whenever twobodies of water or other solvents having differing solute concentrationsare brought into contact with one another and begin to mix. This entropygradient can be physically observed and measured in the well-knownphenomena known as osmosis.

Because the term “osmosis” is associated with a membrane, the term“hydrocrasis” is used as a term for the situation when solvent fluidshaving differing osmotic potentials are contacted and mixed with eachother in the absence of a membrane.

FIG. 1A schematically illustrates conventional forward osmosis through asemi-permeable membrane. Forward osmosis results in the flow of water 10(or other solvent) through a selectively permeable membrane 12 from alower concentration of solute 14 to a higher concentration of solute 14.

FIG. 1B illustrates the condition of reverse osmosis whereby water (orother solvent) 10 under the influence of external pressure is forcedthrough a selectively permeable membrane 12 from a higher concentrationof solute 14 to a lower concentration of solute 14, thus squeezing outor extracting the pure solvent 10 from the solute 14. Reverse osmosis iswidely used in water purification and desalinization plants throughoutthe world. Reverse osmosis consumes work energy.

The osmotic energy potential to be gained from remixing fresh water intosaline ocean water is significant—about 1.4 kJ/kg of fresh water, or theequivalent of about 290 m-head of water for a conventional hydropowersystem. If this source of stored energy could somehow be efficientlyexploited, it could result in the production of enormous amounts ofinexpensive electrical power from a heretofore untapped and continuallyrenewable energy resource.

During recent prototype testing of a similar upwelling device it wasdiscovered, surprisingly, that the amount of upwelling flow achieved interms of kinetic energy of the overall mass flow was in excess of theinput energy into the system in terms of the buoyancy effect and kineticenergy resulting from the fresh water introduced into the up tube.Subsequent experiments using a modified upwelling device have confirmedthat the total hydraulic energy output of such system significantlyexceeds the total hydraulic energy input.

While an exact explanation for this observed phenomena is not fullyappreciated at this time, it is believed that the excess energy outputis somehow attributable to the release of osmotic energy potential uponremixing of the fresh water and the salt water in the up tube.

EXAMPLE 1

The apparatus shown in FIG. 2 was used to measure observed flow rates inthe up tube 40 with different fresh water flow rates introduced into thedown tube 20. Table 1 is a compilation of the results for flow rates atvarious points in the up tube 40 with two different flow rates of freshwater in the down tube 20. The flow rate at Point 1, the flow rate offresh water from the reservoir, and the salinity at Point 2 at theoutlet end 44 of the up tube 40 were measured parameters. The flow rateat Point 3, the outlet end 24 of the down tube 20, was the same as theflow rate at Point 1. The remaining flow rates were calculated using theequations discussed above. TABLE 1 Flow Rates at Various Locations inthe Up Tube Height of Salinity Reservoir at Point 2 Flow (10⁻⁴ m³/sec)(meters) (ppt) Point 1 Point 2 Point 3 Point 4 0.23 34 1.3 45.5 1.3 44.20.55 34 2.4 84.0 2.4 81.6

The results indicate that the flow rate of the mixedsalt-water/fresh-water solution at Point 2 at the outlet end 44 of theup tube 40 far exceeded the flow rate of fresh water at Point 1 andPoint 3. Introducing fresh water into the down tube 20 and allowing thesalt water to flow into the up tube 40 therefore generated higher flowrates at Point 2, at the top of the up tube 40.

In order to demonstrate that this higher flow rate at Point 4 was notdue to transfer of kinetic energy from the fresh water flow coming fromthe down tube 20, the following experiment was performed.

EXAMPLE 2 Flow Rates Through the Up Tube with Salt Water vs. Fresh WaterIntroduced into the Down Tube

For this experiment, a 6″ turbine roof vent was attached to the outletend 44 of the up tube 40. One of the vanes was painted to allow for thecounting of rotations. The reservoir was filled with fresh water havinga salinity of 300 ppm in one experiment and with salt water having asalinity of 36,000 ppm in a second experiment. The reservoir was placedat a height of 0.55 meters above the water level of the salt water inthe pool. The fresh water was then allowed to flow through the down tube20, and the rate at which the turbine rotated was determined. Then, saltwater from the salt water pool was allowed to flow through the down tube20, and the rate at which the turbine rotated was again determined. Theresults are shown in Table 2 below TABLE 2 Turbine Speed with FreshWater vs. Salt Water in Down Tube Down Tube Water Flow Turbine Speed(10⁻⁴ m³/sec) (rpm) Fresh Water (0.3 ppt) 2.4 5.6 Salt Water (36 ppt)2.3 2.3

As illustrated in Table 2, above, the turbine rotated 2.4 times morerapidly when fresh water was introduced into the down tube 20 than whensalt water was used. The higher turbine speed when fresh water wasintroduced into the down tube 20 is a direct indication that the waterflow in the up tube 40 was higher when fresh water rather than saltwater was introduced into the down tube 20 and that the higher observedwater flow rates from the top of the up tube 40 in Example 1 were notdue solely to kinetic energy transfer from the fresh water flow out ofthe down tube 20.

The kinetic energy transferred from the salt water in the down tube 20to the salt water in the up tube 40 would be at least as great (if notslightly greater due to increased density of salt water) as the kineticenergy transferred from the fresh water in the down tube 20. The resultsshown in Table 2 indicate that some, but not all, of the upwelling ofwater in the up tube 40 is due to kinetic energy transfer from the waterintroduced into the down tube 20.

EXAMPLE 3

A series of experiments were carried out using the experimental designdescribed above and as illustrated in FIG. 2, but with down tubes 20having different diameters. With each down tube 20, the flow rates ofthe fresh water in the down tube 20 were varied to determine the effectof different fresh water flow rates on available power. The salinity atthe outlet end 44 of the up tube 40 was measured, and the water flowrates were calculated from the salinity as before. The water flow rateswere used to calculate the available power at Point 2, the outlet end 44of the up tube 40. The available power was then normalized by dividingthe available power by the fresh water flow rate in the down tube 20.The results are shown in Table 4 below. TABLE 4 Normalized PowerProduction vs. Diameter of Up Tube and Fresh Water Flow Rates Down Ratioof Up Power/Fresh Salinity Flow (×0.0001 m³) Tube Tube Area to Water atPoint Point Point Area Down Tube Flow 2 (ppt) Point 1 4 2 (m²) Area(Watts/m³) 31.8 22 259 281 0.000254 69.7 1312 32.6 18 309 327 0.000071249 2715 33.4 5.2 158 163 0.000018 983 1256 31.4 33 334 367 0.00025469.7 1877 32.6 26 446 472 0.000071 249 5664 33.3 7.6 211 218 0.000018983 2047 35.0 5 168 173 0.000010 1770 1559

In all cases, the power per unit volume of fresh water introduced into adown tube 20 of a given diameter increased as the flow rate of freshwater through the down tube 20 increased. Thus, for the down tube 20with an area of 0.000254 m², the power/m³ of fresh water flow increasedfrom 1312 watts/m³ with a fresh water flow rate of 22×10⁻⁴ m³ to 1877watts/m³ with a fresh water flow rate of 33×10⁻⁴ m³. The same trend wasmaintained for the down tubes having areas of 0.000071 and 0.000018 m².Thus, the data illustrates that increasing the fresh water flow rate ina down tube 20 having a given area increased the normalized availablepower output of the device.

Second, although the power per unit volume of fresh water introducedinto the down tube 20 increased with increased volume of fresh waterintroduced into the down tube 20 in all cases, the percent increase inthe power with increase in fresh water flow rate was less for thelargest down tube 20 (0.000254 m² area) than for the other down tubes20. When the fresh water flow rate increased from 22×10⁻⁴ m³/sec to33×10⁻⁴ m³/sec, or by 50%, with the largest down tube 20, thepower/fresh water flow rate increased from 1312 watts/m³ to 1877watts/m³, or 40%. By comparison, when the fresh water flow rate for thedown tube 20 with an area of 0.000018 m²/sec was increased from 5.2 to7.6×10⁻⁴ m³/sec, or 46%, the power/fresh water flow rate increased from1256 watts/m³ to 2047 watts/m³, or 62%, more than 1.5 times as much asfor a comparable percent change in the fresh water flow rate with thelarger down tube 20.

Similarly, when the fresh water flow rate for the down tube 20 with anarea of 0.000071 m³ increased from 18 to 26×10⁻⁴ m³/sec, or 44%, thepower/fresh water flow rate increased from 2715 watts/m³ to 5664watts/m³ or 108%, more than 2.5 times as much as for the largest downtube 20. The efficiency of power production declined with the largestdiameter down tube 20.

These results are shown graphically in FIG. 3. The graphs depictedtherein appear to show that there is an optimum ratio (about 250:1) ofthe area of the up tube 40 relative to the area of the down tube 20 thatmaximizes normalized power production. At ratios higher or lower thanabout 250 the normalized power per unit volume of fresh water declines.

Although a ratio of the area of the up tube 40 relative to the area ofthe down tube 20 of approximately 250 appears to be optimal, the ratiomay range from approximately 5 to 50,000, more preferably from 50 to2000.

The previous examples and discussions illustrate that a suitablyconstructed upwelling apparatus as illustrated in FIG. 2 has thepotential of generating useful power by mixing aqueous liquids havingdifferent osmotic potentials.

FIG. 4 is a simple schematic illustration of one possible embodiment ofa hydrocratic generator 100 utilizing the principles discussed above andhaving features and advantages in accordance with the present invention.The device 100 generally comprises a down tube 20, an up tube 40, and apower plant generator 60. The particular device illustrated in FIG. 4may be adapted for either large-scale deep water applications or forrelatively small-scale or intermediate-scale power generation facilitiesin shallow coastal waters, as desired. For example, the depth of waterillustrated in FIG. 4 may be 10 to 50 meters or more, with the up tube40 being 1-5 meters in diameter.

In a preferred embodiment, fresh water is introduced into the down tube20 in order to power the device. The term “fresh” water as used hereinis to be interpreted in a broad sense as water having an osmoticpotential relative to sea water. Thus, it may be used to describe theinput stream a river discharge, a mountain run-off, a treated sewagedischarge, a melting iceberg, or even runoff from a city storm drainagesystem.

The fresh-water input stream may be conducted though the down tube 20 byapplying pressure at the inlet end 22 of the down tube 20. The pressuremay be provided by a pumping station or with a hydrostatic head pressureresulting from a fluid reservoir at a higher elevation. The pressureapplied at the inlet end 22 of the down tube 20 need only be high enoughto overcome the hydrostatic head at the outlet end 24 of the down tube20.

It has been found that, when fresh water is introduced into the downtube 20, sea water flows into the up tube 40, causing upwelling in theup tube 40 that can be used to generate power with the power generator60. Some of this upwelling effect is due to the increased buoyancy ofthe mixed water in the up tube 20, because fresh water has a lowerdensity than sea water. However, far more upwelling of sea water isobserved than would be expected from this phenomenon alone. It isbelieved that the apparatus and the method is able to harness the energyavailable from the different osmotic potentials of fresh water and seawater. The amount of upwelling and the amount of power that is generatedin the device depend in part on the particular dimensions of the up tube40 and the down tube 20 and the flow rate of fresh water in the downtube 20.

As shown in FIG. 4, the down tube 20 has an inlet end 22 and an outletend 24. The, inlet end 22 is connected to a supply 25 of relativelyfresh water. For example, this fresh water supply 25 may comprise areservoir, pump or other source as desired or expedient. The outlet end24 of the down tube 20 is open such that the fresh water dischargesthrough the outlet end 24 of the down tube 20 into the up tube 40. Inalternative embodiments the outlet end 24 of the down tube 20 may beconnected to an intermediate mixing chamber (not shown) which thendischarges into the up tube 40.

Although the down tube 20 may be any of a variety of diameters, onecriterion is to choose a diameter for the down tube 20 which minimizesthe resistance to fluid flow through the down tube 20. Resistance toflow through a tube decreases as the diameter of the tube increases.Choosing a large diameter for the down tube 20 therefore minimizes theresistance of the tube for a given flow rate.

Another criterion in choosing the diameter of the down tube 20 is tomaximize the amount and efficiency of power generated by the powergenerator 60. When the diameter of the down tube 20 exceeds a certainvalue relative to the up tube 40, it has been discovered that theefficiency of power generation declines as the diameter of the down tube20 is increased further. There is therefore an optimum in the ratio ofthe diameter of the down tube 20 relative to the diameter of the up tube40, and therefore the ratio of the area of the down tube 20 relative tothe area up tube 40, in order to maximize the efficiency of powergeneration. When the ratio of the area of the down tube 20 to the uptube 40 increases beyond the optimal value, the increase in efficiencyof power generation with increased fresh water flow in the down tube 20is less than with a down tube 20 having a smaller area relative to theup tube 40 area. Choosing the diameter of the down tube 20 to maximizepower production therefore involves tradeoffs to choose the maximumdiameter possible without losing power efficiency.

In the embodiment of the apparatus shown in FIG. 4, the outlet end 24 ofthe down tube 20 is located inside the up tube 40. In this embodiment,the outlet end 24 of the down tube 20 is preferably oriented so that theoutlet end 24 of the down tube 20 points upward.

The up tube 40 has an lower end 42 and an outlet end 44. In theembodiment of FIG. 4 both the lower end 42 and the outlet end 44 of theup tube 40 are open. In other embodiments, the lower end 42 of the uptube 40 may contain vanes or other means of directing water flow. Someof these alternative embodiments of the up tube 40 are illustrated inother figures herein

Although the diameters of the lower end 42 and the outlet end 44 of theembodiment of the up tube 40 shown in FIG. 4 are equal, the lower end 42and the outlet end 44 of the up tube 40 may have different diameters inother embodiments. For example, the up tube may be positively ornegatively tapered to form a nozzle or diffuser. Alternatively, the uptube 40 can have a necked-down portion to form an accelerated flowthere-through.

In the embodiment of FIG. 4 the outlet end 44 of the up tube 40 isattached to a flotation system for locating the up tube 40 at apredetermined depth. Other means of locating the up tube 40 at apredetermined depth may also used in place of the flotation system, andthe invention is not limited to the embodiment shown in FIG. 4. Theflotation system shown in FIG. 4 comprises one or more floats 48 and oneor more support cables 50. The float 48 may be formed of Styrofoam, orit may comprise a plurality of individual air bags, drums, or any othersuitable material capable of producing buoyancy.

In some embodiments, the lower end 42 of the up tube 40 is attached tomooring cables 52. The mooring cables 52 extend from the lower end 42 ofthe up tube 40 to anchors 56 fixed on the sea floor. The mooring cables52 and the anchors 56 retain the up tube 40 in a predetermined locationon the sea floor. The lifting force of the float 48 transmitted throughsupport cables 50 retains the up tube 40 at a desired predeterminedvertical orientation.

In the embodiment shown in FIG. 4, the down tube 20 is also attached tomooring cables 52 which extend to anchors 56 on the ocean floor. Themooring cables 52 and anchors 56 hold the down tube 20 in place. Thedown tube 20 is arranged so that it discharges the fresh water into theup tube 40.

Just as choosing an optimal diameter for the down tube 20 involvestradeoffs, choosing the diameter of the up tube 40 also involvesoptimization. Increasing the diameter of the up tube 40 increases theamount of upwelling in the up tube 40 and therefore increases powerproduction. However, increasing the diameter of the up tube 40 increasesboth the size and the cost of the apparatus. Further, increasing thearea of the up tube 40 allows the use of a down tube 20 with a greaterarea without losing efficiency in generating power. The ratio of thearea of the down tube 20 to the area of the up tube 40 is therefore theparameter which is to be optimized rather than the diameter of eitherthe up tube 40 or the down tube 20 alone The optimal diameters for theup tube 40 and the down tube 20 are interdependent on one another,because the ratio of the areas of the two tubes is a more importantparameter in optimizing power production than the area, and thereforethe diameter, or either the up tube 40 or the down tube 20 alone.

Advantageously the down tube 20 and the up tube 40 are not subjected toexcessively high pressures. In the embodiment shown in FIG. 4, the uptube 40 contains the sea water entering from the lower end 42 of the uptube 40 and the fresh water coming out of the outlet end 24 of the downtube 20. Because the up tube 40 is operated at low pressures, the uptube 40 can be constructed of relatively inexpensive and lightweightmaterials such as plastic, PVC, lightweight concrete, and the like.

Although the down tube 20 is subjected to higher pressures than the uptube 40, the pressures in the down tube 20 are typically small. Thus,inexpensive materials can therefore generally be used for both the uptube 40 and the down tube 20. Suitable materials for constructing thedown tube 20 and the up tube 40 include, but are not limited to,polyvinyl chloride (PVC), fiberglass, polyethylene (PE), polypropylene(PP), concrete, gunite, and the like. Alternatively, other materialssuch as stainless steel or titanium may also be used. Because the uptube 20 and the down tube 40 are generally exposed to water ofrelatively high salinity, it is preferable to form the down tube 20 andthe up tube 40 from materials which are resistant to corrosion from saltwater. Although the materials listed above are, in general, resistant tocorrosion, some alloys of stainless steel are not suitable for extendeduse in salt water. If stainless steel is chosen as a material ofconstruction, it is preferable to select an alloy of stainless steelwhich is resistant to corrosion by salt water.

The outlet end 44 of the up tube 40 may extend to or above the surfaceof the sea or may be located at any depth beneath the surface of thesea. In one embodiment, the outlet end 44 of the up tube 40 is locatedin the photic zone so as to bring nutrient-rich deep-sea water to thephotic zone to enhance growth of the organisms in the photic zonethrough mariculture.

The length of the up tube 40 may vary, depending on a variety offactors. The length of the up tube is preferably sufficient to allowcomplete mixing of the fresh water with the salt water, but not so longas to cause unnecessary drag on the water flow. The optimal length willbe determined as that which allows maximum output flow rate and powerproduction for a given range of input fresh-water flow rates. The lengthof the up tube 40 may also be chosen based on a desire to facilitatemariculture, the promotion of growth of organisms in the sea by transferof nutrients from nutrient-rich depths to the nutrient-poor water atlesser depths. If mariculture is practiced, the lower end 42 of the uptube 40 is preferably located at a depth of the sea where largeconcentrations of nutrients are available, and the outlet end 44 of theup tube 40 is preferably located in the photic zone. In this embodiment,the up tube 40 carries nutrient-rich water from the depth of the lowerend 42 of the up tube 40 to the outlet end 44 of the up tube 40 in thephotic zone, where few nutrients are available, thereby enhancing growthof the organisms in the photic zone. The length of the down tube 20 isrelatively unimportant, provided that it is long enough to deliver thefresh water into the up tube.

The power generator 60 generates electricity from the water flow insidethe up tube 40. FIG. 4 shows one simplified form of a power generator 60suitable for use with the present invention. The power generator 60comprises one or more turbines or propellers 62 attached to a shaft 64.In a preferred embodiment, there are a plurality of propellers 62attached to the shaft 64. The shaft 64 is connected to an electricalgenerator 66. When water upwells in the up tube 40, the upwelling waterturns the propellers 62, which in turn rotate the shaft 64. The rotatingshaft 64 drives the electrical generator 66, thereby generating power.

Preferably, one or more shaft supports 68 are provided to support theshaft 64 to minimize wobbling of the shaft 64 while the upwelling waterturns the one or more propellers 62 attached to the shaft 64. In apreferred embodiment, a plurality of shaft supports 68 engage the shaft64 to support the shaft 64 to minimize wobbling. In the embodiment shownin FIG. 4, three shaft supports 68 are present to support the shaft 64,a lower shaft support 68, a middle shaft support 68, and an upper shaftsupport 68. Further details on the shaft supports 68 are given in FIG.7C, described later.

The propellers 62 on the shaft 64 may be inside the up tube 40, abovethe outlet end 44 of the up tube 40, or both inside the up tube 40 andabove the outlet end 44 of the up tube 40. The propellers 62 on theshaft 64 may be located above the middle shaft support 68, below themiddle shaft support 68, or both above and below the middle shaftsupport 68. In the embodiment of FIG. 4, the propellers 62 are locatedinside the up tube 40 below the middle shaft support 68. Similarly, theelectrical generator 66 may be conveniently located above or below thesurface of the water in which the up tube 40 is located. In theembodiment shown in FIG. 4, the electrical generator 66 is located abovethe surface of the water in order to minimize maintenance expense.

FIG. 5 shows an alternative embodiment of a power generator 60. In thiscase, the power generator 60 comprises propellers 62 attached to theshaft 64 both above and below the middle shaft support 68. The shaft 64is attached to the electrical generator 66, which generates electricalpower when the shaft 64 rotates due to the water flow in the up tube 40.Again, the electrical generator 66 of FIG. 5 is located above thesurface of the water. In alternative embodiments, the electricalgenerator 66 may be located below the surface of the water, if desired.

FIG. 6 shows a further alternative embodiment of a power generator 60 inwhich one or more spiral fans 70 are mounted on the shaft 64. Shaftsupports 68 may optionally be provided to minimize wobbling of the shaft64. The one or more spiral fans 70 may be attached to the shaft 64 abovethe middle shaft support 68, below the middle shaft support 68, or bothabove and below the middle shaft support 68. One or more spiral fans 70may be mounted on the shaft 64 on the outlet end 44 of the up tube 40.In an alternative embodiment, one or more spiral fans 70 may be mountedboth inside the up tube 40 and on the outlet end 44 of the up tube 40.In the embodiment of FIG. 6, the spiral fan 70 is attached to the outletend 44 of the up tube 40.

The spiral fan 70 comprises a plurality of spiral vanes 72. The waterflow up the up tube 40 contacts the plurality of spiral vanes 72,turning the one or more spiral fans 70 mounted on the shaft 64. Turningthe one or more spiral fans 70 rotates the shaft 64. The rotating shaft64 drives the electrical generator 66, generating electrical power.Again, the electrical generator 66 may be conveniently located above orbelow the surface of the water, as desired.

In the embodiment of the power generator 60 shown in FIG. 6, bothpropellers 62 and one spiral fan 70 are mounted on the shaft 64. Thepropellers 62 and spiral fans 70 may be mounted on the shaft 64 in anyorder, above, below, or both above and below the middle shaft support68. The propellers 62 and spiral fans 70 may also be mounted on theshaft 64 inside the up tube 40 and/or above the outlet end 44 of the uptube 40. In FIG. 6, propellers 62 are mounted on the shaft 64 inside theup tube 40 below the middle shaft support 68, and the single spiral fan70 is mounted on the outlet end 44 of the up tube 40. The electricalgenerator 66 is located above the water.

FIG. 7A shows a further alternative embodiment of the up tube 40 inwhich the lower end 42 of the up tube 40 is closed. The down tube 20passes through the closed lower end 42 of the up tube 40. Although FIG.7A shows that the down tube 20 is attached to one or more mooring cables52 which are attached to anchors 56 on the ocean floor, the down tube 20may also be supported by the closed lower end 42 of the up tube 40. Theclosed lower end 42 of the up tube 40 of FIG. 7A helps to keep the downtube 20 in position without the need for mooring cables 52 and anchors56.

The up tube 40 of the embodiment of FIG. 7A comprises a plurality ofslots 76, as shown in FIG. 7B. The plurality of slots 76 are open to thesurrounding sea and allow the sea water to enter the up tube 40. One ormore shaft supports 68 are attached to the up tube 40; One possibleembodiment of a suitable shaft support 68 is shown in FIG. 7C. The shaftsupport 68 comprises one or more hydrodynamic cross members 78 and abearing 80. The cross members 78 are attached to the up tube 40 at afirst end and to the bearing 80 at a second end, thereby suspending thebearing 80 inside the up tube 40. The bearing 80 can have a variety ofdesigns such as ball bearings, compression bearings, and the like. Thecross members 78 are preferably hydro-dynamically shaped so as to notslow down water flow in the up tube 40. The shaft support 68 supportsthe shaft 64, minimizing the wobbling of the shaft 64 when the shaft 64rotates.

The power generator 60 of the embodiment shown in FIG. 7A comprises avane drum 90 inside the up tube 40. The vane drum 90 comprises aplurality of rings 92 connected by a plurality of curved vanes 94. FIG.7D shows a sectional view of the vane drum 90. Each curved vane 94 isattached by a first edge 96 to each of the plurality of rings 92. Thecurved vanes 94 are attached to the plurality of rings 92 in a manner sothat the curved vanes 94 form a helical curve when viewed from the side,as shown in FIG. 7A. The helical curved shape of the curved vanes 94improve the efficiency of energy transfer from the water flow throughthe slots 76 on the up tube 40 compared to the efficiency of curvedvanes 94 which are not oriented with a helical curve. FIG. 7D shows thecurved vanes 94 attached to the ring 92 from above as illustrated inFIG. 7A. FIG. 7D also shows the preferred curved surface of the curvedvanes 94 as well as the helical orientation of the curved vanes 94 asviewed from above.

In one preferred embodiment, the vane drum 90 is attached to the shaft64. When the sea water is drawn into the up tube 40 through the slots76, the incoming water contacts the curved vanes 94, rotating the vanedrum 90, which in turn rotates the shaft 64. The rotating shaft 64 turnsthe electrical generator 66, generating power from the upwelling waterin the up tube 40.

FIG. 8A illustrates a further alternative embodiment of the powergenerator 60 comprising two vane drums 90, a first vane drum 90 belowthe middle shaft support 68 and a second vane drum 90 above the middleshaft support 68. In a preferred embodiment, both the first vane drum 90and the second vane drum 90 are attached to the shaft 64 so that theshaft 64 rotates when the vane drums 90 rotate due to the flow of waterthrough the slots 76 into the up tube 40. The rotating shaft 64 rotatesthe shaft of the electrical generator 66, generating electrical power.

In the embodiment of the up tube 40 shown in FIG. 8B, there arepreferably two sets of slots 76 in the up tube 40 and two vane drums 90.In another embodiment, there are two vane drums 90 as in the embodimentshown in FIG. 8A, but the up tube 40 comprises only a single set ofslots 76 in the up tube 40, as in the embodiment of the up tube 40 shownin FIG. 7B.

FIG. 9A shows an alternative embodiment of the down tube 20 in which aplurality of holes 110 are present in the side of the down tube 20. FIG.9B shows a view of the outlet end 24 of the down tube 20 of FIG. 9A. Theoutlet end 24 of the down tube 20 of FIG. 9A is sealed except for asingle hole 110. In alternative embodiments, a plurality of holes 110may be provided in the outlet end 24 of the down tube 20. The freshwater flowing through the down tube 20 of FIG. 9A flows out of theplurality of holes 110 and into the up tube 40. Although the embodimentof the apparatus shown in FIG. 9A shows the alternative down tube 20with the embodiment of the up tube 40 of FIGS. 4-6 with an open lowerend 42, the down tube 20 of FIG. 9A may also be used with the embodimentof the up tube 40 such as shown in FIGS. 7A or 8A with a closed lowerend 42.

FIGS. 10A and 10B show another embodiment of the down tube 20 in whichthe down tube 20 separates into a plurality of secondary down tubes 120In the embodiment shown in FIG. 1A, there are a plurality of holes 110in the secondary down tubes 120, similar to the embodiment of the downtube 20 shown in FIG. 9A. FIG. 10B shows a sectional view of the downtube 20 of the embodiment of FIG. 10A from below. In the embodimentshown in FIG. 10B the outlet end 24 of each of the five secondary downtubes 120 is closed except for a single hole 110. In the embodiment ofthe down tube 20 of FIGS. 10A and 10B, the fresh water that isintroduced into the down tube 20 exits the holes 110 to enter the uptube 40.

In other embodiments the down tube 20 may separate into a plurality ofsecondary down tubes 120, as in the embodiment of the down tube 20 ofFIG. 10A, but there are no holes 110 in the secondary down tubes 120,and the outlet ends 24 of the secondary down tubes 120 are open. In thisembodiment of the down tube 20 (not shown), the fresh water which isintroduced into the down tube 20 exits the open outlet ends 24 of thesecondary down tubes 120 to enter the up tube 40.

FIG. 11 shows an alternative embodiment of the down tube 20 in which thedown tube separates into a plurality of secondary down tubes 120. In theembodiment shown in FIG. 11, the down tube 20 separates into a pluralityof secondary down tubes 120 outside of the up tube 40. In the embodimentshown in FIG. 11, there are no holes in the secondary down tubes 120, asin the embodiments shown in FIGS. 9A and 10A. In other embodiments thereare a plurality of holes 110 in the secondary down tubes 120.

Although the embodiment of the apparatus shown in FIG. 11 shows thealternative down tube 20 with the embodiment of the up tube 40 of FIGS.4-6 with an open lower end 42, the alternative down tube 20 of FIG. 11may also be used with the embodiment of the up tube 40 such as shown inFIGS. 7A or 8A with a closed lower end 42.

FIG. 12 shows another embodiment of the down tube 20 in which the downtube 20 terminates in a hub 122. The hub 122 forms a cap on the downtube 20 and rotates freely on the down tube 20. A plurality of spokeoutlets 124 are fluidly connected to the hub 122. The plurality of spokeoutlets 124 emerge at approximately a right angle from the hub 124 andthen bend at a second angle before terminating in a spoke discharge 126.The spoke discharge 126 may have an open end or a partially closed endwhere the water from the down tube 20 discharges. The embodiment of thedown tube 20 shown in FIG. 12 is similar to a rotating lawn sprinkler.The hub 122 is attached to the shaft 64, which is in turn connected withthe electrical generator 66. In the embodiment shown in FIG. 12, thereis no up tube 40.

When fresh water flows through the down tube 20 and is discharged out ofthe spoke outlets 124, the hub 122, shaft 64, and electrical generator66 rotate, generating electrical power. In the embodiment shown in FIG.12, the energy generated by the electrical generator 66 comes almostexclusively from the kinetic energy from the water emerging from theplurality of spoke discharges 126, because there is no up tube 40 ormeans of generating power from hydrocratic energy generated from themixing of fresh water from the down tube 20 with water of high salinity.

FIG. 13 shows another embodiment of the down tube 20 similar to theembodiment of FIG. 12, with a hub 122, a plurality of spoke outlets 124,and a plurality of spoke discharges 126 at the ends of the spoke outlets124. The embodiment of FIG. 13 differs from the embodiment of FIG. 12 inthat the spoke discharges 126 discharge the fresh water from the downtube 20 into an up tube 40 with an open lower end 42 and a plurality ofpropellers 62 attached to the shaft 64. The fresh water which exits thespoke discharges 126 into the up tube 40 causes upwelling in the up tube40, rotating the propellers, which in turn drive the shaft 64. The shaft64 drives a electrical generator 66 (not shown), generating electricalpower.

In the embodiment of the apparatus shown in FIG. 13, the shaft 64 isrotated both by the discharge of water from the spoke discharges 126rotating the hub 122 and by the upwelling in the up tube 40 turning thepropellers 62, which in turn rotate the shaft 64. The energy generatedin the embodiment of the apparatus shown in FIG. 13 is therefore acombination of kinetic energy from the rotation of the hub 122, shaft64, and electrical generator (not shown) from the fresh water ejectedfrom the spoke discharges 126 and from hydrocratic energy generated fromthe upwelling in the up tube 40 from the mixing of fresh water from thespoke discharges 126 mixing with the water of high salinity entering theup tube 40 from the lower end 42.

FIG. 14 illustrates another embodiment of the up tube 40 in which thereare a plurality of nested up tubes 40 having increasing diameters. Thelower end 42 of each of the plurality of nested up tubes 40 is open.Fresh water is introduced into the down tube 20 causing upwelling in theplurality of up tubes 40 when the water of high salinity enters the openlower ends 42 of the nested up tubes 40.

Any of the embodiments of power generators 60 can be combined with theembodiment of the nested up tubes 40 of FIG. 14. For example, in oneembodiment, the propellers 62 of FIGS. 4 and 5 may be used as a powergenerator 60 in combination with the nested up tubes 40 of FIG. 14. Inanother embodiment, the power generator 60 may comprise one or morespiral fans 70, as shown in FIG. 6.

FIG. 15 shows another embodiment of the up tube 40 and power generator60. In the embodiment of FIG. 15, a plurality of turbines 130 aremounted on a shaft 64 inter-spaced between a plurality of stators 132.The stators 132 direct the water flow into the turbine blades of theturbines 130 to increase the efficiency thereof. The shaft 64 isconnected to an electrical generator 66 (not shown). When water upwellsin the up tube 40, the upwelling water turns the turbines 130, which inturn rotate the shaft 64 and the electrical generator 66, generatingpower.

In the embodiment shown in FIG. 15, the portion of the up tube 40surrounding the turbines 130 and stators 132 comprises a nozzle 134 andan expander 136. The nozzle 134 reduces the diameter of the up tube 40in the portion of the up tube 40 around the turbines 130 and stators 132from the diameter of the remainder of the up tube 40. By reducing thediameter of the up tube 40 with the nozzle 134 in the portion of the uptube 40 surrounding the turbines 130, the upwelling water is forced intoa smaller area and is accelerated to a higher velocity water flow thatcan be harnessed more efficiently by the turbines 130. Nozzles 134 andstators 132 can also be used with other embodiments of the powergenerator 60 illustrated herein.

FIG. 16 is a schematic illustration of a possible large-scale commercialembodiment of a hydrocratic generator having features and advantages ofthe present invention. While a particular scale is not illustrated,those skilled in the art will recognize that the device 200 isadvantageously suited for large-scale deep-water use 100-500 meters ormore beneath sea level. The up tube 240 extends upward and terminates atany convenient point beneath sea level. The diameter of the up tube maybe 3-20 meters or more, depending upon the desired capacity of thehydrocratic generator 200. This particular design is preferably adaptedto minimize environmental impact and, therefore, does not result inupwelling of nutrient rich water from the ocean depths.

Sea water is admitted into the device from an elevated inlet tube 215through a filter screen or grate 245. The filter removes sea life and/orother unwanted objects or debris that could otherwise adversely impactthe operation of generator 200 or result in injury to local sea lifepopulation. If desired, the inlet tube 215 may be insulated in order tominimize heat loss of the siphoned-off surface waters to colder water ator near full ocean depth. Advantageously, this ensures that thetemperature and, therefore, the density of the sea water drawn into thegenerator 200 is not too cold and dense to prevent or inhibit upwellingin the up tube 240.

The sea water is passed through a hydraulic turbine power plant 260 ofthe type used to generate hydraulic power at a typical hydro-electricfacility. The turbine and generator assembly is illustrated in moredetail in the cutaway view of FIG. 16. Water enters the turbine 261through a series of louvers 262, called wicket gates, which are arrangedin a ring around the turbine inlet. The amount of water entering theturbine 261 can be regulated by opening or closing the wicket gates 262as required. This allows the operators to keep the turbine turning at aconstant speed even under widely varying electrical loads and/orhydraulic flow rates. Maintaining precise speed is desirable since it isthe rate of rotation which determines the frequency of the electricityproduced.

As illustrated in FIG. 16, the turbine is coupled to an electricgenerator 266 by a long shaft 264. The generator 266 comprises a large,spinning “rotor” 267 and a stationary “stator” 268. The outer ring ofthe rotor 267 is made up of a series of copper wound iron cells or“poles” each of which acts as an electromagnet. The stator 268 issimilarly comprised of a series of vertically oriented copper coilsdisposed in the slots of an iron core. As the rotor 267 spins, itsmagnetic field induces a current in the stator's windings therebygenerating alternating current (AC) electricity.

Referring again to FIG. 16, the sea water is discharged from the turbineinto the up tube 240. Fresh water is introduced into the base of the uptube 240 by down tube 220. The mixing of fresh water into saline seawater releases the hydrocratic or osmotic energy potential of the freshwater in accordance with the principles discussed above, resulting in aconcomitant pressure drop (up to 190 meters of head) across thehydraulic turbine 260. This pressure drop in conjunction with theinduced water flow upwelling through the up tube 240 allows forgeneration of significant hydropower for commercial power productionapplications without adversely affecting surrounding marine culture.

With reference to FIG. 18 of the drawings, this embodiment shows an uptube 40 having an open lower end 42 and an open outlet end 44. A downtube 20 is provided which enters the up tube 40 through the lower end42, and extends to a point approximately midway along the length of theup tube, where it is sealed by a cap 302. A shaft 64 extends upwardlyfrom the cap 302, extending to a generator, not shown in FIG. 18, butsubstantially similar to generators shown in some of the Figuresdescribed above.

Although in the embodiment shown in FIG. 18, the down tube 20 is shownas extending to a point approximately midway up the length of the uptube 40, this construction may, in practice, vary widely according tothe conditions, length of the up tube 40, and other apparatusparameters. Thus, the down tube 20 may extend only a short distance intothe up tube 40, or it may extend well beyond the midpoint thereof, to aselected height.

The down tube 20 comprises an outside portion 304, located outside ofthe up tube 40, and an inside portion 306, located within the up tube40. The outside portion 304 and inside portion 306 of the down tube 20are connected to each other by a rotational connector 308, which, in theembodiment shown in FIG. 18 is at the level of the open lower end 42.However, this rotational connector 308 could be configured on the downtube 20 at any appropriate vertical position of the down tube 20.

The rotational connector 308 permits rotation of the inside portion 306relative to the outside portion 304, as will be described.

The inside portion 306 has a plurality of radial apertures 310, whichmay be randomly disposed on the inside portion 306, or specificallylocated, such as beneath a turbine 62, according to the selectedconfiguration of the generator. Fresh water entering the down tube 20from a supply source or reservoir passes through the rotationalconnector 308, and into the inside portion 306, where it must exitthrough one of the radial apertures. The cap 302 mounted at the top endof the inside portion 306 prevents any water or liquid from the downtube 20 from exiting the inside portion 306, except through the radialapertures 310.

The inside portion 306 and shaft 64 are secured appropriately inposition by shaft supports 68 to prevent wobbling or axial displacementthereof, as has already been described above in other embodiments.

In operation, fresh water exiting the down pipe 20 through the radialapertures 310 is mixed with water of higher salinity entering the lowerend 42 of the upper tube 40. The energy produced by the mixing of thewater of higher salinity and lower salinity drives turbine 62, which inturn rotates the inside portion 306, the cap 302, and the shaft 64. Thisembodiment permits accurate selection of apertures 310 for releasing ofthe fresh water into the up tube 40, in a manner that is fixed withrespect to the turbines 62. Since the radial apertures 310 and turbines62 are both rotating, the precise location of mixing, and the optimaleffect thereof of driving the turbine 62, can be exploited to improvethe efficiency and hence the energy produced by the apparatus of theinvention. This is achieved by the use of the rotational connector 308which allows relative rotation of the inside portion 306, but ensures noleakage or fresh water escape from the down tube 20 at the position ofthe rotational connector 308.

FIG. 19 shows a variation of the apparatus shown in FIG. 18, includingthe up tube 40, the down tube 20 having an outside portion 304, and aninside portion 306, the outside and inside portions 304 and 306respectively being connected by the rotational connector 308. A cap 302is provided at the top end of the inside portion 306, and a series ofturbines 62 are mounted on the inside portion 306, which has a pluralityof selectively placed radial apertures 310. The apparatus in FIG. 19differs from the embodiment shown in FIG. 18 by the existence of aclosure piece 320 over the lower end 42 of the up tube 40. Since theclosure piece 320 prevents sea water from entering the lower end 42 ofthe up tube 40, a plurality of holes 322 are provided at locations inthe wall of the up tube 40, as shown in FIG. 19B, through which the seawater is introduced to the interior of the up tube 40. One advantage ofthe embodiment shown in FIGS. 19A and 19B is that the sea water can beintroduced at the most efficient point, thereby facilitating control ofthe precise points or areas at which the sea water as well as the freshwater are first introduced and allowed to mix. This factor, coupled withthe orientation of turbines 62 on the inside portion 306, can be used tostreamline the efficiency of the apparatus. As was the case with respectto FIG. 18, the fresh water is only allowed to exit through the radialapertures between the rotational connector 308 and the cap 302, at aposition, flow-rate and orientation which can be controlled andmanipulated to advantage.

In FIG. 20 of the drawings, a further embodiment showing a variation ofthose illustrated in FIGS. 18 and 19 of the drawings is illustrated. Inthis embodiment, an up tube 40 is provided, as well as a down tube 20including an outside portion 304, an inside portion 306 having aplurality of radial apertures 310, and a cap 302. At the lower end 42, aclosure piece 320 is provided. In the embodiment shown in FIG. 20, therotational device 308 is positioned outside of the up tube 40 andclosure piece 320 so as to permit rotation of both the inside portion306 of the down tube 40, and the up tube 20, in response to energyproduction which causes rotation of the turbine 62. Thus, rotation aboutthe connector 308 as a result of forces on the turbines 62 therebyrotates the closure piece 320, up tube 40 and the inside portion 306 ofthe down tube 20.

As was the case in the embodiment shown in FIGS. 19A and 19B, sea waterwill enter the up tube 40, not through the lower end 42, but through aseries of holes 322 of the type shown in FIG. 19B. Alternatively,instead of having a plurality of holes 322, one or more slits may beprovided in the wall of the up tube 40, such as those shown in FIGS. 7Bor 8B of the drawings.

The embodiment of FIG. 20 is yet another variation by means of which theprecise location of entry of the fresh water and sea water respectivelyinto the up tube 40 can be controlled and exploited to derive maximumenergy and power following hydrocrasis and the energy released thereby.

FIG. 21 of the drawings shows a variation of the hydrocratic generatorof the invention which uses neither vanes nor turbines on the shaft 64,but rather a helical screw 330 mounted on the shaft, and which is causedto rotate in response to the energy released by mixing of the water withdifferent salinities. Such forces acting on the helical screw 330 rotatethe shaft 64, which in turn transmits rotational forces to the generatorfor use as described above.

FIG. 22A of the drawings shows an alternative embodiment for deliveringfresh water from the down tube 20 to a precise location with respect tothe fan blades. As shown in FIG. 22A, an inside portion 306 of the downtube 20 has a plurality of fan blades 62, also referred to as turbines,mounted thereon Instead of exiting the inside portion 306 through aplurality of apertures, the fresh water in the inside portion 306 is fedthrough a fan tube 336 which is mounted on the underside 338 of the fanblade 62. Towards the outer extremity 340 of the fan blade 62, the fantube 336 includes a U-shaped section 342, terminating in an outlet 344.Thus, fresh water enters through the inside portion 306, flows along thefan tube 336, into the U-shaped section 342, and exits through outlet344. In the embodiment shown in FIGS. 22A and 22B, the fresh water thusflows from the interior pipe through a series of smaller pipes locatedunder the fan blades 62 (or helical screw, if this embodiment is used),to the outer edge of the fan blades 62. The direction of flow isreversed so the fresh water exits in a flow direction which is towardsthe center of the up tube 40.

The embodiment shown in FIGS. 22A and 22B allows the apparatus to takeadvantage, once more, of controlling the exit areas for the saline andfresh water, thereby pinpointing the reaction location for maximumenergy production and/or use of such energy in a manner which rotatesthe fan blades optimally. As with the other embodiments, the insideportion 306 of the down tube 20 is attached to a rotating shaft, whichin turn attaches to a generator or power mechanism which uses or storesthe energy so produced.

Reference is now made to FIG. 23 of the drawings showing yet a furtherschematic representation of an embodiment of the invention. FIG. 23shows some of the basic components only, and is mainly intended toillustrate the various locations and multiple turbines which may be usedwith the system. As such, only the basic apparatus is shown, but it mayof course incorporate features and components as described in any one ormore of the previous embodiments This also applies to all embodimentsdescribed below.

In FIG. 23, the up tube 400 is positioned within a body of water 402,the up tube 400 having an upper end 404 and a lower end 406. Typically,the body of water 402 is the ocean, and water of relatively highhumidity will enter the up-tube 400 through the lower end 406, and movetowards the upper end 404. However, other models and variations are ofcourse within the scope of this invention.

A down tube 408 is provided, and extends from a reservoir 410 at oneend, with the other end 412 of the down pipe/tube discharging into theup tube 400 at or near the lower end 406. As has been described above,water from the reservoir 410 will have relatively low salinity, and mixwith the relatively high salinity water entering through the lower end406 of the up tube 400. As has already been described, the mixing of therelatively low and relatively high salinity water produces energy, andpower generators are positioned to capture this energy. In FIG. 23, afirst turbine 414 is provided near the upper end 404 of the up tube 400to capture the energy and therefore generate power. It is to be notedthat a second turbine 416 is positioned near the reservoir 410, alongthe down tube 408. Note that the second turbine 416 is shown near thereservoir 410 in FIG. 23, but it may be placed at other locations alongthe down tube 408. The flow of water through the down tube 408 drivesthe second turbine 412 and energy derived therefrom is used to producepower.

Additionally, a third turbine 418 is provided near the lower end 406 ofthe up tube 400. The third turbine 418 is positioned so as to takeadvantage of flow of water from the body of water 402 into the up tube400, and capture and produce power.

Thus, it will be seen from FIG. 23 that various turbines may be placedaround the system to take advantage of water flow not only as the resultof the mixing of the relatively low and relatively high salinity water,but also to place turbines in other positions where they may be drivenby the flow of water, either through the down tube 408, or upon enteringor being driven through the up tube 400. Note that in FIG. 23, thesecond turbine 416 is shown outside of the body of water 402, althoughof course it can be placed at a lower level along the down tube 408, andmay additionally or alternatively be located in the body of water 402.

In FIG. 24 a of the drawings, another mechanism whereby water may beintroduced from a source of low salinity into the up tube isillustrated. Thus, in very schematic form, FIG. 24 a shows an up tube430, positioned substantially vertically, with an upper end 432 and alower end 434, as has already been described. Water of relatively highsalinity enters the lower end 434, passes into the up tube 430, andeventually is discharged through the upper end 432. While in the up tube432, the relatively high salinity water is mixed with a relatively lowsalinity water delivered by a down pipe or tube 436. The down pipe 436is connected to a source of relatively low salinity water, and extendsto the lower end 434 of the up tube 430, and has a discharge opening 438through which the relatively low salinity water is introduced into theup tube 430.

Further, the down pipe 436 has attached thereto a secondary down pipe440 which leads off the down pipe 436 and is spirally or helicallywrapped around the up tube 430. The secondary down pipe 440 has aplurality of holes 442 arranged along its length, and these holesregister with corresponding holes in the up tube to permit water to passfrom the secondary down pipe 440, through the up tube 430 and into theinterior thereof. FIG. 24 b shows a cross-section of the secondary pipe440, wrapped around the up-tube 430, with the holes 442. In thisembodiment, therefore, the relatively low salinity water, or freshwater, is introduced into the up-tube 430 not only at the low end 434thereof, but also along multiple points of entry corresponding to theholes 442. This may facilitate mixing in a more thorough manner and maytherefore also enhance the ability to capture additional power as aresult thereof.

Reference is now made to FIG. 25 which shows a further embodiment of theinvention in schematic form. Once more, there is provided an up tube450, and a down pipe 452. The up tube 450 has a lower end 454 and anupper end 456. The up tube 450 is located in a body of water, such asthe ocean, and relatively high salinity water enters through the lowerend 454, passes through the up tube 450 and is discharged through theupper end 456.

The down pipe 452 conveys water from a fresh water source, or water ofrelatively low salinity, or waste water which has been, or is to betreated, therethrough, and comprises the discharge opening 458 near thelow end 454 of the up tube 450. Additionally, a sleeve 460 is formedaround the up tube 450, and is supplied with water from the down pipe452 through a branch pipe 462. The branch pipe 462 conveys water fromthe down pipe 452 to the inside of the sleeve 460, and holes in the uptube 450 allow water introduced into the sleeve 460 to enter the up tube450 for mixing with the relatively high salinity water entering throughthe lower end 454. It will be appreciated that this embodiment shows avariation of that shown in FIG. 24 a, providing additional points ofentry of fresh water, or relatively low salinity water, to enhancemixing over a wider volume.

FIG. 26 illustrates a further embodiment of the invention in schematicform, and shows an up tube 470 having an upper end 472 and a lower end474. A down pipe 476 conveys fluid of relatively low salinity into thelower end 474 of the up tube 470. Additionally, a first branch pipe 478and a second branch pipe 480 branch from the down pipe 476, and havedischarge outlets 482 and 484 respectively within the up tube 470. Thedown pipe 476 itself continues and has a discharge outlet 486 near thelower end 474 of the up tube 470. FIG. 26 illustrates an embodimentwhere fluid is delivered to the up tube 470 at several locations, oncemore, to facilitate mixing and to enhance the ability to captureadditional power from the mixing process.

In FIG. 27, an up tube 490 has an upper end 492 and a lower end 494. Adown tube 496 extends from a source of relatively low salinity water,and has a discharge outlet 498 near the lower end 494 of the up tube 40.The down tube 496 also has a first branch pipe 497 and s second branchpipe 500 which respectively connect to a ring 502 and a ring 504 whichcircumnavigates the up tube 490 at various locations along its length.The first and second branch pipes 497 and 500 respectively deliver wateror fluid to the rings 502 and 504 respectively, and the rings 502 and504 have multiple holes therein through which water can pass to enterthe up tube 490. FIG. 27 b is cross-section through the up tube at thelocation of a ring, providing a further detail as to the configuration.Once more, this particular form of the invention allows a more diversedelivery of low salinity fluid into the up tube 490 to provide a morebroad-based and effective mixing mechanism which in turn facilitatescapturing of additional power from the mixing process.

Reference is now made to FIG. 28 of the drawings showing in schematicform yet another embodiment of the invention. In this particularembodiment, the hydrocratic generator of the invention is intended foruse in conjunction with, for example, a sanitation district which mayoptionally incorporate a desalination plant. In FIG. 28, there is showna body of water 520 having a water surface 522. Within the body of water520, there is located a vertical or up tube 524 having an open upper end526 and an open lower end 528. The up tube 524 is preferably locatedadjacent a land mass 530, which has built thereon various structures,including a sanitation district plant 532 and a desalination plant 534.These two plants provide, respectively, fluid of relatively highsalinity, and fluid of relatively low salinity, so that the mixingthereof within the vertical tube 524, along the lines described in theseveral embodiments above, produce energy which can be captured by apower generator for storage and subsequent use.

A sewer line 538 extends from the sanitation district plant 532, and hasa discharge outlet 540 at or near the lower end 528 of the vertical tube524. There is also a pipe or brine line 542 for transmitting fluid fromthe desalination plant to the inside of the up tube 524. Within thetube, the discharge contents from the sewer line 538, and the brine line542, each of which has different relative salinity levels, results in amixture which produces energy. A power generator, which may be in theform of a turbine, is not shown in FIG. 28 of the drawings, but may bepositioned at or near the upper end 526 of the vertical tube 524, so asto capture the energy of the mixture. Additionally, turbines or powergenerators may be placed at other locations, such as in either one ofthe sewer line 538 or brine line 542.

As an alternative, the brine line 542 and sewer line 538 may bejuxtaposed so that each discharges into the vertical tube in the reverseform as shown in FIG. 28. The lower end 528 of the vertical tube 524 isopen, so that water from the body of water 520, such as an ocean, alsoenters the vertical tube.

In FIG. 28, the turbine or power generator may be above the upper end526, outside of the vertical or up tube 524, or it may be at the levelof the upper end 526 or even below it within the tube. Further, theremay be more than one turbine or power generators arranged relative tothe tube 524 so as to maximize the capture power in the most efficientmanner to optimize energy produced by the mixing of the various fluids.

It should be noted that in all of the embodiments above, the relativelylow salinity fluids and the relatively high salinity fluids may comprisefresh water and ocean water respectively, but the invention is certainlynot limited to such an arrangement. In fact, the hydrocratic generatorof the invention may be used in any situation which can exploit theenergy produced by the mixing of relatively low salinity fluid andrelatively high salinity fluid, irrespective of their nature. Thus, thefluid may be fresh water, ocean water, desalinated water, sanitation orwaste water, or any other fluid, without limitation, the combination ofwhich with one other such fluid will produce the necessary energy byvirtue of mixing.

FIG. 29 shows a further embodiment of the invention. The hydrocraticgenerator 560 comprises a top tube 562 and an lower tube 564. The toptube 562 has open upper and lower ends 566 and 568. The lower tube 564also has open upper and lower ends 570 and 572. The top tube 562 has aturbine 574 at or near its lower end 568. The top tube 562 is of smallerdimension than the lower tube 564 so that the lower end 568 of the toptube 562 is received with in the upper open end 570 of the lower tube564. A brine line 576 feeds the top tube 562. There is a gap between thelower tube 564 and the lower end 568 of the top tube 562. This gap ispreferably sufficiently large so that the percentage at the bottom ofthe lower tube will about 36% ppt or less.

FIG. 30 shows a hydrocratic generator 580 having a top tube 582 and alower tube 584. These tubes are arranged more or less as the top tube562 and lower tube 564 are shown in FIG. 29 of the drawings. There mayof course be dimensional variations in the sizes and relative sizes ofthe top and lower tubes. In FIG. 30, there is a first portion 586 of abrine line 588, and second portion 590 of the brine line 588. Theseportions are demarcated generally by a head 592. The second portion 590of the brine line 588 extends into the top tube 582 and has a pluralityof holes 594 along its length. The head is shown in a different view inFIG. 31 of the drawings. A turbine 596 is located at or near the lowerend of the top tube 582.

In the embodiments shown in FIGS. 29 and 30 of the drawings, the lowerend of the top tube preferably extends a short distance downwardly ofthe upper end of the bottom tube and a gap is provided therebetween.

Reference is now made to FIG. 34 of the drawings, which shows ahydrocratic generator contained in a pool 600. The pool 600 comprises achamber 602 defined by side walls 604. A hydrocratic generator 606 isshown in schematic form, and is located within the chamber 602 of thepool 600. As seen in FIG. 35 of the drawings, the hydrocratic generator606 is mounted on a supporting structure 608, which may be adjustable,and which places the hydrocratic generator 606 in a predetermined andpreselected space within the pool, as may be determined to be an optimalposition.

A cooling water/waste water discharge inlet 610 conveys the coolingwater/waste water into the chamber 602, and, as best seen in FIG. 35.The inlet 610 comprises an end 614. The end 614 is approximately at theopen end of the inlet 616 of the hydrocratic generator. The discharge612 passes through the inlet 610, and exits the inlet 610 at the openended inlet 616 of the hydrocratic generator.

A separate brine conduit 620 conveys brine therethrough from a sourceand into the pool 600. The brine fills the chamber 602, and rises to alevel which is above that of the hydrocratic generator 606. The level ofthe discharge 612 is such that the hydrocratic generator 606 is locatedcompletely within the discharge 612.

It will therefore be appreciated that the pool is essentially filledwith the brine conveyed from a source. Cooling water/waste waterdischarge passes through the inlet 610, and exits therefrom near theopen-ended inlet 616 of the hydrocratic generator. As the coolingwater/waste water exits the inlet 610, it draws in brine from the poolsurrounding the hydrocratic generator 606, as indicated by arrows 622and 624. AS such, a mixture of cooling water/waster water discharge andbrine enters the hydrocratic generator 606, and the difference inosmotic potential, as already described in detail above, is used todrive a turbine 626. The turbine is connected to a generator 630 wherethe power may be stored, channeled or otherwise disposed of in a largenumber of different ways.

FIG. 34 shows a side view of the hydrocratic generator illustrated inFIG. 34 of the drawings. As will be seen in both FIGS. 34 and 35 of thedrawings, the brine in the pool, as well as the mixture exiting thehydrocratic generator at end 632, eventually exits the pool 600, and isdischarged to the ocean through discharge pipe 634.

Reference is now made to FIGS. 32 and 33 of the drawings which show asystem somewhat similar to that illustrated and described in FIGS. 34and 35, where the various structures are essentially the same, except aswill be described below. In FIG. 34, the pool is filled with brine, andthe cooling water/waste water discharge exits the inlet 610 at theopen-ended inlet 616 of the hydrocratic generator 606. In contrast, theembodiment shown in FIGS. 32 and 33 of the drawings show a pool 600which is filled with cooling water/waste water discharge which entersthrough the pipe 610, and fills the pool to a level above the positionof the hydrocratic generator. In FIGS. 32 and 33, the brine conduit 620discharges the brine at the open end 615 of the hydrocratic generator606. In the hydrocratic generator, a mixture of both brine and thecooling water/waste water discharge travel, and provide the necessaryosmotic potential to drive the turbine 626, which produces power storedin the generator 630.

In the embodiments shown in FIGS. 32 and 33 on the one hand, and FIGS.34 and 35 on the other, it will be appreciated that the relativeproportions of cooling water/waste water discharge and brinerespectively in the hydrocratic generator 606 will differ. Furthermore,the size, diameter, dimensions and other physical attributes of theinlet 610 in FIG. 34 of the drawings may be varied, and the samedimensions and the like of the brine inlet 620 in FIG. 32 may be varied,so that a desired relative proportion of cooling water/waste waterdischarge and brine is obtained.

In the embodiment shown in FIG. 32 of the drawings, the open end 616 ofthe hydrocratic generator may be somewhat flared with a frusto-conicalwall 638, best seen in FIG. 32 of the drawings.

FIG. 36 of the drawings shows another embodiment, in this case with thehydrocratic generator arranged vertically, as compared with FIGS. 32 to35, where the hydrocratic generator is mounted in a horizontal orsubstantially horizontal position. It will be appreciated that mountingof the hydrocratic generator may also be at any suitable angle betweenvertical and horizontal, as may best be calculated to produce an optimumamount of osmotic potential, and therefore drive the turbine for maximumpower output.

In FIG. 36, there is illustrated a closed tank 646, in which iscontained a hydrocratic generator 648. The hydrocratic generator has anopen lower end 650, and an open upper end 652. Near the open upper end652, there is mounted a turbine 654, connected to a generator 656, forcapturing and storing energy, and has been described previously in thisspecification, and will not be repeated at this point.

The closed tank 646 is fed by a brine line 658, from which brine from asource is discharged into the closed tank 646. The closed tank 646 isalso fed by a cooling water or effluent line 660, which enters throughthe base of the closed tank 646 and discharges at approximately thelevel of the lower open end 650 of the hydrocratic generator 648. Bothcooling water or effluent discharged through the pipe 660, and brinecontained within the closed tank, enter the hydrocratic generator 648,and the osmotic potential produced by the mixing of these two fluidswill drive the turbine 654, to provide energy to generator 656 as hasbeen described. The mixture exiting through the upper open end 652 ofthe hydrocratic generator 648, as well as brine contained within theclosed tank, but surrounding the hydrocratic generator 648, arepermitted to exit through the overflow or outflow pipe 662.

The closed tank 646 illustrated in FIG. 36 of the drawings may belocated on land, or it may be located under water, either fully ofpartially.

Reference is now made to FIG. 37 of the drawings, which shows anembodiment similar to, but not identical with, that shown in FIG. 36 ofthe drawings. The structure of the closed tank 646 (reference numeralsin FIG. 37 will be the same as those used in FIG. 36, since thestructure is essentially identical) is fed with a pipe 658 that injectscooling water or effluent into the close tank. In this embodiment, thepipe 660 feeds brine to the lower open end of the hydrocratic generator648. The embodiment in FIG. 37 thus shows the reverse use of the coolingwater or effluent on the one hand, and the brine on the other, both ofwhich, however, are introduced into the hydrocratic generator to createthe osmotic potential for driving the turbine 654. Once more, differentproportions or relative amounts of the cooling water oreffluence/effluent and brine respectively, may be introduced into thehydrocratic generator depending upon the dimensions, sizes, etc. of theopen ends of the hydrocratic generator, as well as the line 660.

Reference is now made to FIG. 38 of the drawings which shows analternate underwater configuration of the hydrocratic generatorillustrated in FIGS. 36 and 37 of the drawings. In FIG. 38, there isshown a tank 678, but with an open top 680. The tank itself may belocated either above the ocean, or below the ocean surface. Within thetank there is formed a hydrocratic generator 648, having the turbine 654and generator 656. In the embodiment shown in FIG. 38, brine isintroduced through the pipe 658, while cooling water or effluent isintroduced through the pipe 660. However, this could be reversed so thatthe opposite situation would prevail.

The embodiment shown in FIGS. 32 to 38 may, for example, be optimallyused where a desalination plant and a power plant or a sanitationdistrict may be working together. Thus, the sanitation district wouldpipe the effluent over to the desalination plant, so that at least aportion of effluent from the sanitation runs through the tank, andthereafter becomes incorporated into the overflow which is sent out tosea with the rest of the effluent. The mixture of brine and waste water,as already described with respect to these Figures, drive thehydrocratic generator to generate power.

In one embodiment, a power plant pipes over a portion of the sea waterthat was used for cooling purposes, to be run through the tank. Theoverflow then goes back into the outflow line, where it will be runthrough a desalination device to bring the salinity within less than 4%of the ambient salinity of the sea water and, possibly, generate morepower.

More than one such hydrocratic generator of the type described in FIGS.32 to 38 may be used in combination, wherein, for example only, onehydrocratic generator is formed within a pool on land, and a secondhydrocratic generator is formed in the ocean, that generates power fromthe combined desalination and effluent and/or waste water.

Reference is now made to FIG. 39 of the drawings which shows a down tube702 having an upper end 704 and a lower end 706, the down tube 702 beinghollow and open at each of its ends 704 and 706. A turbine or propeller708 is shown near the lower end 706 of the down tube 702. The turbine708 can be of many different configurations, formats and embodiments ashas been discussed with respect to other Figures in this application andspecification.

Above the down tube 702 there is shown schematically a brine line 710.

At selected points along the down tube 702 there are formed at leastone, but preferably a plurality, of openings 712, with each of theopenings having adjacent thereto a cup or scoop 714. The cup 714 has anopen upper end 716, so that fluid can flow from the ambient, or areasurrounding the down tube, through the open end 716, in the opening 712,and into the interior of the down tube 702.

The down tube 702 is typically located in an ambient solution 718, andtypically the salinity of the ambient solution 718 will be less than thesalinity of the brine entering through the brine line 710.

In FIG. 40 of the drawings, a down tube 720 is schematicallyillustrated, with similar components and structure to that in FIG. 39.To the extent possible, the same reference numerals have been used todescribe the same features and elements. The down tube 720 illustratedin FIG. 40 of the drawings has, as will be observed, a tapering effect,wherein the diameter of the down tube 720 at the lower end 706 is lessthan the diameter of the down tube at the upper end 704. In thisparticular embodiment shown in FIG. 40 there is a fairly consistenttaper from the upper end 704 to the lower end 706, but it is within thescope of the invention that the degree or extent of tapering may varyalong the length of the down tube, and, further, that the tapering mayoccur only along certain sections, while other sections may be ofsubstantially consistent diameter.

FIG. 41 of the drawings shows yet a further embodiment of a down tubewhich may be constructed in accordance with the present invention. FIG.41 shows a down tube 722, and once more, to the extent possible,corresponding reference numbers for corresponding components will beused, as was done in FIGS. 39 and 40.

In FIG. 41, the down tube 722 tapers from a wider diameter upper end 704to a lesser diameter lower end 706, and the plurality of cups or scoops704 are distributed at selected locations on the outer side of the downtube 722.

In FIG. 41, there is also shown a series of successively wider down tubeelements 724, comprising an upper down tube element 726 and a lower downtube element 728, the lower down tube element 728 being of substantiallyconsistent diameter, but of greater diameter than the upper down tubeelement 726, also of fairly consistent diameter. Note that the upper andlower down tube elements 726 and 728 may also be tapered, and may eitherincrease in diameter from upper end to lower end, or decrease indiameter from upper end to lower end.

Note that the down tube elements 724 shown in FIG. 41 of the drawingsare used with a down tube 722 of decreasing diameter, as shown also inFIG. 40, but it is important to note that the down tube element 724 mayalso be used with the down tube 702 which has a diameter ofsubstantially consistent size over its length.

As illustrated in FIGS. 39, 40 and 41, the down tubes have openings orperforations 712 at various locations with the cup or scoops 714optionally located over the openings 712. Some or all of the openings712 may be present without the cup 714. The cup 714 and opening 712arrangement is constructed for the purpose of increasing the volume ofambient solution 718 which enters the down tubes 702, 720 and 722.

With respect to these Figures, each hydrocratic engine may typicallyhave fixed interior dimensions. Thus, as the water traveling through thehydrocratic engine, or down tube, increases, the velocity of the waterwill also increase. As such, the tapering designs of the down tube(s)may have the desired effect of increasing the volume of water passingthrough the down tube over a given period of time, at the same timeincreasing the velocity of the water and the amount of power produced bythe hydrocratic engine. It will be appreciated of course, that increaseof volume and velocity of water passing over the turbine or generator708 will drive the turbine 708 with increased energy so that more powercan be produced.

Reference is now made to FIG. 42 of the drawings showing a furtherembodiment of a hydrocratic generator, constructed in accordance withone aspect of the invention. As will be seen in the drawing, thehydrocratic generator comprises a chamber 730 defining an upper space732 and a lower space 734. The upper and lower spaces 732 and 734 beingseparated by wall 736. A down tube 738 is located within the upper space732, and comprises a tapering configuration with an upper end 740 havinga larger diameter than the lower end 742. The wall of the down tube 738has at least one and preferably a plurality of openings 744.

The wall 736 has an opening 746, and the lower end 742 of the down tube738 has a portion which extends through this opening 746, in a mannersuch that a seal is formed between the wall of the down tube 738 and thewall 736. As will be described below, any fluid contained in the space732 will not be able to move or pass through the opening 746, which willbe sealed in an appropriate manner with the down tube 738.

The upper space 732 of the chamber 730 has a brine inlet 748 and a freshwater inlet 750. The brine inlet has a discharge nozzle 752 which islocated immediately above the upper end 740 of the down tube 738. Theupper space 732 also has an overflow outlet 754 near the upper endthereof.

In the lower space 734 of the chamber 730, there is constructed animpeller 756 which is attached to a drive shaft 758, the drive shaftitself being attached to a generator 760. The drive shaft 758 extendsthrough the wall of the chamber 730, since, as will be seen in FIG. 42,the generator 760 is located outside of the chamber.

The lower space 734 has a drain outlet 762, and may in one embodimentconnect to the overflow outlet 754, which may have a larger diameter, sothat either overflow from chamber 730, or discharge from lower space 734are conveniently removed through the same structure. It will, however,be appreciated that the drain outlet 762 may discharge independently ofthe overflow outlet 754.

In operation, the hydrocratic generator as shown in FIG. 42 operateswhen fresh water is introduced into the upper space 732 through thefresh water inlet 750. Eventually, the upper space 732 fills with freshwater, and may fill up to level 764, after which excess fresh wateroverflows into the overflow outlet 754 for discharge into the ocean. Atthe same time, brined fluid is introduced through the brine inlet 748,and the nozzle 752 is below level 764. The brine discharged through thenozzle 752 enters into the down tube 738. As the brine fluid moves downthrough the down tube 738 it is mixed with fresh water which enters thedown tube either through the open upper end 740 of the down tube, and/orthrough one of the plurality of openings 744. The mixing has the effectalready described in previous embodiments of the invention, and themixture is discharged through a nozzle 766 located at the very lower endof the down tube 738, into the lower space 734. As the mixture exits thenozzle 766, the mixture drives the propeller 756 which in turn, throughthe drive shaft 758, powers the generator 760, which in turn is able tostore and thereafter transmit power in the usual way as described. Themixture of fluid entering the lower space 734 ultimately drains throughthe drain outlet 762 located in the floor of the chamber 730, and isdischarged to the ocean either through a separate outlet, or by joiningwith the overflow outlet 754, as already described.

Note that the down tube 738 in FIG. 42 is shown in a taperedconfiguration, but this down tube 738 may be of fairly uniform diameterin other configurations, or tapered in the opposite direction. Further,the existence of the opening 744 as well as their number, shape andsize, can vary in accordance with the invention. Furthermore, at leastsome of the openings 744 may have attached thereabout the cup or scoopas has been described and illustrated with respect to FIGS. 39, 40 and41 of the drawings. It should also be noted that the down tube 738 inFIG. 42 is not to scale, and the Figure is schematic for the purposes ofillustrating the components and overall structure of the invention.

Reference is now made to FIG. 43 of the drawings showing a furtheraspect of the invention. The hydrocratic generator shown in FIGS. 43 and44 are for most purposes the same, except for the location thereof. FIG.43 shows a hydrocratic generator of the invention when mounted orcontained within a substantially closed reservoir, while FIG. 44 showsthe hydrocratic generator of generally the same structure when locatedin the ocean.

In FIGS. 43 and 44 there is shown a hydrocratic generator including adown tube, generally designated with the reference numeral 770. The downtube 770 is generally in a substantially vertical orientation. The downtube 770 has a number of portions, as will now be described.

The down tube 770 has a funnel portion 772 at the top thereof, with awider diameter open end 774, tapering down to a narrower lower end 776.At the lower end, the funnel portion 772 transitions with a circulartube portion 778. The generally round or circular tube portion 778transitions to a square tube portion 780, with a transition 782therebetween. At the lower end of the square portion 780, there isformed a venturi tube portion 784, with a transition 786 formed therebetween. The venturi tube portion 784 tapers from a wide diameter end788 to a narrow diameter end 790, the venturi tube portion 784 having adischarge opening 792 at its narrow end 790.

A brine inlet line 794 transmits brine to the down tube 770 and has adischarge opening 796 just above the open end 774 of the funnel portion772.

It will be noted that the square tube 780 has at least one, andpreferably a plurality of openings 798 through which water from theambient area around the down tube 770 can be drawn into the down tube770.

With specific reference to FIG. 43, the down tube 770 as described aboveis formed within a reservoir 800, having side walls and at least a basewall. There is a fresh water inlet 802 for allowing fresh water into thereservoir 800, and an overflow outlet 804 for overflow. A portion of theventuri tube 784 portion extends through an opening 806 in the lowerwall of the reservoir 800, and the mixture of liquids discharged fromthe opening 792 is used to drive an impeller, turbine or the like, ashas been described with reference to other embodiments.

In FIG. 44 of the drawings, the down tube 770 is formed within the ocean808, but is otherwise of fairly similar construction to that shown inFIG. 43.

In the down tube illustrated in both FIGS. 43 and 44, brine enters thefunnel portion 772 of the down tube 770, and flows through the down tubetowards the discharge opening 792. The brine liquid is mixed with freshwater, or ocean water, as the case may be, the mixture driving theliquid outwardly form the discharge opening for the purposes of poweringa turbine or other appropriate device, as has been described.

Reference is now made to FIG. 45 of the drawings. In FIG. 45, ahydrocratic generator 814 is shown including a down tube indicatedgenerally by the reference numeral 816. In FIG. 45 the down tube 816 isgenerally cylindrical and of fairly consistent diameter along itslength. However, it may be tapering of the down tube 816 along itslength, or a portion thereof.

The down tube 816 has a meshed screen portion 818, and a substantiallysolid portion 820. At the lower end of the solid portion there is formeda turbine 822, impeller or other device by means of which the energyproduced within the down tube can be harnessed.

It will be seen that the down tube 816 shown in FIG. 45 is formed in theocean 824, below the surface 826 thereof. However, it should also beunderstood that a down tube 816 having the construction andconfiguration of that as illustrated in FIG. 45 may also be formed in abody of fresh water.

At the upper end of the down tube there is provided a brine line 828having a discharge opening 830 which discharges brine immediately abovethe upper end of the down tube. Thus, brine enters the down tube 816 atthe top thereof and through the open end, the brine water in the downtube thus having a higher concentration of solutes than in thesurrounding ocean water 824. As such, hydrocratic forces cause waterfrom the ocean 824 to pass through the meshed screen portion 818 intothe down tube 816, such movement being facilitated by the lowerconcentration of solute to the higher concentration solute respectively.In FIG. 45, the down tube 816 has a fixed diameter and the additionalwater passing through the mesh screen portion 818, introduced into thedown tube, results in an increasing velocity of the water passing andmoving through the down tube 816, thereby increasing the kinetic energyof the water in the hydrocratic engine. These hydrocratic forces will,at least to a large extent, prevent interior water, or water mixtureflowing within the down tube 816, from exiting the down tube 816 throughthe meshed screen portion 818, and into the ocean. Such prevention offlow will occur up to a back pressure point, and this point may beselected and determined based on various parameters including, but notlimited to sizes and dimensions of the down tube 816, respectiveconcentrations of the brine and ocean water respectively, as well assuch other determining factors.

Other Applications/Embodiments

In the preferred embodiments discussed above, the up tube 40 is locatedin a body of water of high salinity and high negative osmotic potentialsuch as an ocean or a sea. The water of high salinity and high negativeosmotic potential enters the up tube 40 in a ratio of greater than 8:1salt water to fresh water, more preferably 30:1 salt water to freshwater, and most preferably about 34:1 or higher. The mixing of the freshwater of low negative osmotic potential with the sea water of highnegative osmotic potential in the up tube 40 causes upwelling and drawssea water into the up tube 40 through the openings. The upwelling waterin the up tube 40 rotates propellers 62, spiral fans 70 or turbines 130,261, which are attached to a drive shaft 64, 264. The rotating shaft 64,264 turns the electrical generator 66, 266 generating electrical powerfrom the difference in osmotic potential between the fresh waterintroduced into the down tube 20 and the water of high salinity whichenters the up tube 40 through the openings in the up tube 40.

Because the method depends on having solutions of different osmoticpotentials exiting the down tube 20 and entering the up tube 40, it ispreferable that the source of fresh water exiting the down tube 20 andthe source of the water of high salinity entering the up tube 40continue to have different osmotic potentials over time so that powergeneration continues over a long period of time. For example, if thebody of water of high salinity surrounding the up tube 40 is small, thefresh water exiting the down tube 20 can dilute the water of highsalinity after exiting the up tube 40, reducing the difference inosmotic potential between the fresh water and the water of highsalinity. Reducing the difference in osmotic potential between the freshwater exiting the down tube 20 and the water of high salinity enteringthe up tube 40 reduces the amount of energy available. It is thereforegenerally advantageous that the body of water of high salinity have alarge volume. Locating the up tube 40 in a large body of water havinghigh salinity such as the ocean or the Great Salt Lake is therefore apreferred embodiment.

Alternatively, the invention can be operated between bodies of saltwater having different salinity or between waters at different depths ofthe same body of water. For example, the salinity and temperature of seawater is known to vary with depth and location. In the Hawaiian islands,at a depth of 1000 meters, the ambient water temperature isapproximately 35° F., with a salinity of approximately 34.6 ppt. Thesurface temperature is approximately 80° F. with a salinity ofapproximately 35.5 ppt. Thus, an osmotic energy potential (albeit small)exists between the surface waters and the waters at 100 meters depth.

While the present invention is disclosed in the context of generatingpower by directly contacting and mixing fresh water with sea water in anapparatus located in the ocean, it is to be understood that theapparatus and method are not limited to this embodiment. The techniquesand concepts taught herein are also applicable to a variety of othersituations where aqueous solutions having differing osmotic potentialsare available. For example, in one embodiment, the apparatus and methodmay be applied to a concentrated brine from a desalinization plant beingmixed with the less-concentrated brine in sea water. In anotherembodiment, a treated sewage effluent, a fresh water stream, can bemixed with sea water. If desired, an osmotic membrane or osmotic waterexchange plenum may be provided at the outlet end of the down tubeand/or at the outlet (top) of the up tube in order to increase theefficiency of energy production. The apparatus and method may thus beapplied to a wide range of applications in which two solutions ofdiffering osmotic potential are available.

The various embodiments of the invention disclosed and described hereinare exemplary only. As such, these example embodiments are not intendedto be exhaustive of all possible ways of carrying out the invention oreven the most economical or cost-efficient ways of carrying out theinvention on a commercial scale. Accordingly, it is intended that thescope of the present invention herein disclosed should not be limited bythe particular disclosed embodiments described above, but should bedetermined only by a fair reading of the claims that follow.

1. A mixing apparatus for mixing first salinity fluid with a secondsalinity fluid, the mixing apparatus comprising: a down tube having aside wall, an open upper end and an open lower end, and a plurality ofapertures selectively located in the side wall of the down tube, atleast some of the apertures having an arm member with an opening thereinabout the aperture to facilitate inflow of fluid to the down tubethrough the openings; a fluid inlet and a fluid outlet at the open upperend and open lower end respectively of the down tube, wherein the firstsalinity fluid in use enters the down tube through the fluid inlet andthe apertures and is discharged therefrom through the fluid outlet; anda feed tube having a first end connectable to a source of secondsalinity fluid having a salinity different to the first salinity fluidand a second end for introducing the second salinity fluid to the fluidinlet of the down tube to mix the first salinity fluid with the secondsalinity fluid to form a fluid mixture.
 2. A mixing apparatus as claimedin claim 1 further comprising at least one power generator associatedwith the down tube, the power generator being driven by the mixing ofthe first salinity fluid with the second salinity fluid.
 3. A mixingapparatus as claimed in claim 2 wherein the power generator comprises aplurality of propellers and a shaft, the propellers being located in thehousing, and an electrical generator coupled to the shaft for generatingelectrical power.
 4. A mixing apparatus as claimed in claim 1 whereinthe second salinity fluid is selected from the group consisting of oceanwater, fresh water, waste water, desalination water, or a mixture of oneor more thereof.
 5. A mixing apparatus as claimed in claim 1 wherein thefirst salinity water is selected from the group consisting ocean water,waste water, or a mixture thereof.
 6. A mixing apparatus as claimed inclaim 1 wherein the down tube tapers from a first diameter upper end toa second diameter lower end, the first diameter being greater than thesecond diameter.
 7. A mixing apparatus as claimed in claim 1 wherein aportion of the down tube comprises at least two substantially co-axialcylindrical elements.
 8. A mixing apparatus as claimed in claim 7wherein at least some of the cylindrical elements are of differentdiameter and the cylindrical elements are arranged descending from theupper end of the down tube by increasing diameter.
 9. A mixing apparatusas claimed in claim 1 wherein the arm member comprises a cup shapedmember fastened to the down tube about an aperture thereon with theopening of the cup shaped member facing upwardly.
 10. A hydrocraticgenerator system comprising: a container having an upper chamber and alower chamber sealed from the upper chamber, the upper chamber foraccommodating a body of fluid having a first salinity; a first feedinlet in the upper chamber of the container through which the fluidhaving a first salinity can be discharged into the container; a downtube having an upper inlet end and a lower outlet end, the down tubebeing located primarily in the upper chamber of the container with theoutlet end thereof discharging into the lower chamber; a second feedinlet through which fluid having a second salinity can be dischargedinto the upper chamber of the container such that the fluid having thesecond salinity mixes with the fluid having the first salinity in thedown tube; and a discharge means from the lower chamber to facilitatedischarge of the mixed fluids.
 11. A hydrocratic generator system asclaimed in claim 10 wherein the down tube tapers from a first diameterupper end to a second diameter lower end, the first diameter beinggreater than the second diameter.
 12. A hydrocratic generator system asclaimed in claim 10 wherein the down tube comprises a plurality ofapertures therein at selected locations.
 13. A mixing apparatus formixing first salinity fluid with a second salinity fluid, the mixingapparatus comprising: a down tube having a side wall and an open upperend and an open lower end, the down tube having a funnel shaped portionat the upper end, a cylindrical portion below the funnel shaped portion,a substantially square portion below the cylindrical portion and aventuri tube portion below square portion.
 14. A mixing apparatus asclaimed in claim 13 further comprising a first transition portionbetween the cylindrical portion and square portion and a secondtransition portion between the square portion and the venturi tubeportion.
 15. A mixing apparatus as claimed in claim 13 furthercomprising a plurality of apertures in the square shaped portion of thedown tube.
 16. A mixing apparatus as claimed in claim 13 configured formounting in a reservoir.
 17. A mixing apparatus as claimed in claim 13configured for mounting in the ocean.
 18. A mixing apparatus for mixingfirst salinity fluid with second salinity fluid, the mixing apparatuscomprising: a down tube having a side wall and an open upper end and anopen lower end, the side wall being comprised of a meshed screen portionand solid portion below the meshed screen portion; a fluid inlet and afluid outlet at the open upper end and open lower end respectively ofthe down tube, wherein the first salinity fluid in use enters the downtube through the fluid inlet and meshed screen portion and is dischargedtherefrom through the fluid outlet; a feed tube having a first endconnectable to a source of second salinity fluid having a salinitydifferent to the first salinity fluid and a second end for introducingsecond salinity fluid to the fluid inlet of the down tube to mix thefirst salinity fluid with the second salinity fluid to form a fluidmixture.
 19. A mixing apparatus as claimed in claim 18 wherein thedimension of the meshed screen portion is selected based on the overallsize of the down tube, as well as the respective salinities of the firstand second salinity fluids.
 20. A mixing apparatus as claimed in claim18 wherein the meshed screen portion has a mesh size which can be variedon the down tube.
 21. A mixing apparatus as claimed in claim 20 whereinthe meshed screen portion has a plurality of mesh sizes over the lengthof the meshed screed portion on the down tube.